f355 cruising speeds

Sorry to sound a bit harsh Steve but it sounds like you have not driven a 3 pedal car much. Its hard to describe want your wanting. Want you need is a good demo. Wish I was in your area or you in mine. That would be the only way to show you what you want to know.

 

You are wrong is so many ways. One does not drive around at 5000 rpm at all times. You have to vary the rpm greatly. Another way of describing what your saying is that it is ok to sit on the couch all day....your body will also carbon up. Your body like the 355 needs its legs stretched every time you take it out. You can drive at 3500 rpm for a while but this car also needs to rev up a lot. Never drive it at a constant rpm whatever the rpms. The beauty of these cars is the feeling of the pull when accelerating from 3500rpm to 7500rpm and the odd time higher. That's what this car is all about. If you don't then you bought the car purely as a show piece period. As for the comment that this is not a race engine.....well its as close as you can get for a road car at the time and the challenge cars are run with the same engines without any mechanical mods. They raced and continue to race them all over the world and they are one brut of an engine. If you own a 355 and drive it mostly around 2500 to 3000 rpm.....you will be spending a lot of cash on a rebuild sooner than later.

 

I am just wanting to know what the short term and long term outcome of this engines mechanical limits if I were to run thru the gears at excessive rpms say 5k and up. Is winding the engine up that much going to cause damage in the short term. Will it last?

 

Absolutely not and yes. These engines want the revs. Not only that but you will enjoy the car and drive it the way it was meant to be. Man, I wish I could take you for a ride. My friend and mechanic knows these cars as good as anyone....he was in on the design of many Ferraris, mostly the 430.

 

+1

 

Sorry Steve, my "banging it off the rev limiter" comment here was not intended to be a clinic of driving a 6 speed Ferrari. That term is racing slang for a driver who revs the engine until the electronic rev limiter, designed to protect the engine from over revving, engages and then he shifts after a few cycles of ignition interruption.

When it comes to driving there are no stupid questions! I have been coaching professional racing drivers for almost 30 years, so I have heard them ALL

The reason you are frustrated with the responses here is that there is no ONE right answer to your question. That is the beauty and "fun" of having a stick in the floor rather than an automatic. It all depends on the driving conditions and your "mood. If you are in a hurry, by all means use the entire rev range for all the upshifts, at 8,000RPM the car is making great power and will reward you with a big rush to any speed you want. If you are more relaxed, then shifting at 3,000 might be more appropriate. The important thing is the RPM "drops", rather than the top revs. If you shift too early, say 2500RPM (in low gears) then the engine will be turning too slowly to accelerate very hard in the next higher gear../ As you get out of 4th gear, 5th and 6th gears tend to be "cruising gears" so dropping into them at 3,000 or 3500 RPM is fine as long as you dont need to accelerate hard, pass anyone or climb a steep grade.. So you see there is no right answer, just drive it and experiment with you the engine feels and sounds. You will get the hang of it quickly. Most of all, dont worry, you are not going to hurt it...Unless you are BANGING IT OFF THE REV LIMITER all the time!

 

Perfect answer and perfect way to end the answer with a grin. Thanks so much for you expert advice!

 

True.

Another item to your corrections list..while it is true the 355 engine is not a "racing engine"...it shares many aspects of its architecture with proper racing engines. Things like a 180 degree crank, dry sump lubrication, minimalist accessory drives, more than 4 valves per cylinder etc.....these are characteristics shared with racing engines and rarely seen on the street. An engine design like this will produce power differently, need to be driven and maintained differently and will also wear differently than typical production car engines. That is the case here.

This notion that RPM = Wear is difficult to argue with. Certainly an engine run at red line on a dyno for a few days may fail before an engine run at idle for the same amount of time. But engine wear is more directly related to "Load" rather than RPM. For example an 8 cylinder engine spreads its power production over twice as many parts as a 4 cylinder engine and a 12 cylinder engine spreads the loads out even further. That doesn't necessarily mean that an 8 cylinder engine will last twice as long or a 12 three times as long does it? The factors here are many and complex including piston speed, displacement, valve geometry and more. A Top Fuel engine turns over only about 35 times during a run and is mostly junk at the end. You could argue that the right speed to cruise at is the one that requires the least amount of throttle opening to maintain. That is generally a higher RPM for a given speed.

To say that RPM=Wear maybe be true in the simplest sense, but no one here is going to wear out ANY engine by running at 2500 instead of 4000 RPM on the freeway over the engines life span. Take this off your list of Ferrari 355 concerns, there are lots of other worries to take it's place!

I am sure the engineers here can explain this more clinically, but my message remains...STFU and drive the damn car!

 

complete and utter nonsense. Your body is organic, an engine is not.

No one is suggesting you drive at a steady rpm. My point is that you can drive along on the highway at 2500rpm-3500rpm with no worries whatsoever. If the car is running properly, you should not be experiencing significant carbon issues.

If you are suggesting to rev it for fun, thats an entirely valid perspective, but it has nothing to do with the health of the motor.

Challenge cars all run the same motor. I could have a race series filled with honda accords. That doesn't make them race motors.

If you can provide to me statistically significant evidence (not mechanic xyz said abc) that running the engine the majority of the time at 2500rpm to 3000rpm in steady state cruise will cause the engine to require a more immediate rebuild, I'll accept your theory.

The 355, like any modern car, can be driven a variety of ways without issue. No, you should not lug the motor (3000rpm isn't lugging), no you should not beat on it when its cold. Other than that, driving it normal (i.e. some lower rpm cruising, some higher rev acceleration runs, etc) is just fine.

180 degree crank=ok
dry sump...fine, but common enough
minimalist accessory drives? alternator, air conditioning? Water pump is driven by the timing belt so still parasitic
more than 4 valves for cylinder? This is uncommon period, race cars or not. Even the 430 went back to 4v per cylinder.

And yet none of these things has anything to do with how the car should be driven. The only point you may have is that the 355 engine has so little torque down low that you risk lugging it on even slight inclines. I still wager this is very rare, especially at 3k rpm, but YMMV.

Obviously a single factor such as RPM is not the only determinant of engine wear. That said, all else equal, higher revs=higher wear. To your point, if you want the least load, you should run around at peak power by very little throttle...and yet, no one seems to do that.

You are right, no one will suffer engine damage from running the scant miles that y'all do at 2500rpm vs. 4000rpm or vice versa, so really, drive it however you want.

 

Amen-The end!

 

I got it! Everyone is right and some are wrong. I don't know what happened to the OP. A thread is like planting a seed and watching it take off I suppose. Thanks again for all the technical data and info. I for one just wanted to make sure my inexperience with the car wouldn't ruin it until such a time I received some drives ed. Thanks so much!

 

It will last thousands of miles even shifted at redline. It's much worse for these engines to sit as the acid in the oil will pit the titanium con rods and aluminum engine parts. These cars were raced hard in the challenge series and were very robust. You are worrying about nothing.

 

After a couple of days of thought, I ame up with seeral <semi>counter arguments

A) High RMP at High Throttle will cause wear increase.

B) But at light to moderate throttle, the wear on the cylinder walls and rings pretty much goes away--since cylinder pressures are very moderate and the materials have been chosen for the high load high RPM case.

C) Reciprocating forces are quadradic with respect to RPMs. So, with a 355-like engine (which will not grenade at 9000 RPMs) running at 6000 RPMs you literally have only 40% of the reciprocating foces at work, and these are easily held by the oil films in the motor.

D) crankshaft forces are quite small at light to moderate throttle. The Crank is ballances wrt the reciprocating weight so the journal pressures are low. Light throttle makes the main bearing forces low, and also make the torsional forces low.

E) the valve train forces remain almost independent of throttle position

So most of the high loaded sections of the motor see vast reduction in the forces at play leaving only the valve train to wear at pretty much the same rate as at higher throttle positioins.

So, I believe that for the most part, running down the road at 6000 RPMs will not wear out your engine any faster than running downthe road at 3000 RPMs (AT the SAME speeds).

F) as to lugging, the headers and intake velocity stacks don't really start to work until 3500 RPMs with some interesting flow characteristics in the 2500 RPM range.

So if you want to stay away from potential carbon buildup and CAT issues, there are some reasons to keep the motor above 3000 RPMs.

But overall in the 3000 to 6000 RMP band at light to moderate throttle positions, worry not; something else will break first........